I propose to continue along the path of my past decades work in cancer epidemiology. That work will entail: 1) Analyses of routinely-collected data on cancer incidence and survival. Local and national data will be used, both to generate clues as to etiologies of cancer and to address practical issues of cancer prevention and treatment. 2) Population-based case-control studies of cancer, including studies of: a) ovarian cancer in relation to talc exposures and exogenous hormones; b) breast cancer in young women in relation to prior induced abortion; c) death from colorectal cancer in relation to non-use of Hemoccult testing and other methods of early detection ; and d) condyloma acuminata, a strong risk factor for several forms of cancer, in relation to posible "host" factors related to the occurrence of this condition. 3) Refinement of epidemiologic methods relevant to the study of cancer.